Experimental procedure for fundamental studies of reinforcing steel corrosion processes

Abstract

An experimental procedure is presented for use in fundamental studies of reinforcing steel corrosion. An electrochemical corrosion cell is presented that incorporates a cement paste film cast against a polished section of reinforcing steel surface, while isolating other portions of the reinforcing steel surface from corrosion activity. The cement paste is prepared without admixed chlorides, then allowed to hydrate in a curing chamber for a period of three days prior to introduction of chlorides to the cell. The cell is transferred from a humid curing chamber to chloride solution exposure, where chlorides diffuse through the cement paste film to the steel surface and causes corrosion damage. This experimental procedure is well suited for detecting subtle changes in the passive state of reinforcing steel by either ac or dc electrochemistry. Ac impedance spectroscopy can also monitor the continuing hydration of cement paste. Chemical and microstructural analysis of the steel/cement paste interface is also possible upon disassembly of the cell.